The module needs to be passed the full URL to Riak’s stats endpoint.
For example:

myriak:url:http://myriak.example.com:8098/stats

With no explicit configuration given, the module will attempt to connect to
http://localhost:8098/stats.

The default update frequency for the plugin is set to 2 seconds as Riak
internally updates the metrics every second. If we were to update the metrics
every second, the resulting graph would contain odd jitter.